Cyclone separators are typically found in applications which require the removal of particulates from a fluid stream. This fluid stream may be a liquid such as water, or it may be a gas such as air. Cylones are very useful for pollution control applications, removing particulate matter from exhaust gases before these gases are directed to baghouses or scrubbers or are discharged directly to the atmosphere.
Many exhaust gas applications operate at high temperatures such that the cyclone itself is exposed to these high temperatures. Thus, the cyclone experiences dimensional growth due to thermal expansion. It is desirable to be able to operate at these high temperatures, sometimes in excess of 1,500xc2x0 F., while maintaining a relatively cool skin temperature below 650xc2x0 F. so that inexpensive materials of construction, such as carbon steel, may be used for the vessel body of the cyclone. In order to accomplish this, it is industry standard to utilize refractory material, such as Vibecast refractory, lining the inside of the cyclone vessel body.
While the use of the refractory allows the high temperature operation while maintaining a much cooler cyclone vessel body, it causes a problem when it comes to connecting the cyclone outlet pipe, operating at this higher temperature, to the much cooler cyclone vessel body. In the prior art, a bolted, flanged connection has been made between the outlet pipe and the cyclone vessel body, with a gasket to seal the gap between the two flange faces. This unyielding connection does not allow for relative movement between the outlet pipe and the cyclone vessel body. Since this relative motion must occur due to the differences in thermal expansion between the outlet pipe and the cyclone vessel body, the result is very high induced stresses on the welds as well as on the bolts, resulting in eventual failure, requiring down time and expense to repair and replace the damaged parts. The severe operating conditions also tend to cause the nuts to become frozen onto the bolts, making it very difficult to remove and replace a worn outlet pipe. These difficulties have generally limited operation of the cyclones to temperatures in the range of 1,600xc2x0 F. to 1,800xc2x0 F.
The present invention provides an arrangement for mounting the outlet pipe onto the vessel body of a cyclone operating at very high temperatures, without experiencing the failures and limitations present in the prior art. The present invention eliminates the use of flanges or bolts, substantially reduces the thermal-expansion-induced stresses on the welds, and allows operation at temperatures well in excess of 1800xc2x0 F. In fact, this present invention will allow operation of the cyclone in a coke calciner application where the exhaust gases entering the cyclone are at temperatures in excess of 2,250xc2x0 F.
The present invention provides for nesting of the outlet pipe into an opening in the vessel body so that the weight of the outlet pipe keeps the pipe in place and there is no need for bolts. The preferred frustro-conical shapes of the nesting surfaces properly center and locate the outlet pipe, and the contact surface area between the two parts is generally sufficient to seal the surfaces without the need for gaskets, although a gasket can be used if desired. This connection permits relative expansion and contraction of the vessel and the outlet pipe without affecting the connection or seal between the parts. It also results in a simpler, faster installation with no bolts, quick and automatic location of the outlet pipe in the outlet opening, and easy removal and replacement of the outlet pipe without the need to remove or install bolts.